X4 Pharmaceuticals, Inc

Previous wording

We are a biopharmaceutical company developing, and commercializing novel therapeutics for the treatment of rare hematology diseases. We continue to progress our global, pivotal Phase 3 clinical trial, (the “4WARD” trial) to evaluate the efficacy, safety, and tolerability of oral, once-daily mavorixafor (with or without stable doses of G-CSF) in people with congenital, acquired primary autoimmune, or idiopathic chronic neutropenia who are experiencing recurrent and/or serious infections. The 52-week trial is a randomized, double-blind, placebo-controlled, multicenter study aiming to enroll up to 176 patients, with full enrollment expected in Q3 2026. The FDA has granted Fast Track designation to mavorixafor for the treatment of chronic neutropenia. Chronic neutropenia is defined as periods lasting more than three months persistently or intermittently where there are abnormally low levels of neutrophils circulating in the blood, and may be idiopathic (of unknown origin), cyclic (episodes typically occurring every three weeks), or congenital (of genetic causation). Chronic neutropenia disorders are rare blood conditions similarly characterized by increased risks of infections and cancer due to abnormally low levels of neutrophils in the body. In all cases, the CXCL12/CXCR4 pathway is the key regulator of neutrophil release from the bone marrow.

Current wording

We are a biopharmaceutical company developing and commercializing novel therapeutics for the treatment of rare hematology diseases. We continue to progress our global, pivotal Phase 3 clinical trial, (the “4WARD” trial) to evaluate the efficacy, safety, and tolerability of oral, once-daily mavorixafor (with or without stable doses of granulocyte colony-stimulating factor (“G-CSF”)) in people with congenital, acquired primary autoimmune, or idiopathic chronic neutropenia (“CN”) who are experiencing recurrent and/or serious infections. The 52-week trial is a randomized, double-blind, placebo-controlled, multicenter study aiming to enroll up to 176 patients, with full enrollment expected by the end of the third quarter of 2026. The U.S. Food and Drug Administration (“FDA”) has granted Fast Track designation to mavorixafor for the treatment of CN, which is defined as periods lasting more than three months persistently or intermittently where there are abnormally low levels of neutrophils circulating in the blood, and may be idiopathic (of unknown origin), cyclic (episodes typically occurring every three weeks), or congenital (of genetic causation). CN disorders are rare blood conditions similarly characterized by increased risks of infections and cancer due to abnormally low levels of neutrophils in the body. In all cases, the CXCL12/CXCR4 pathway is the key regulator of neutrophil release from the bone marrow.

Previous wording

We have one commercially approved product, XOLREMDI ® (mavorixafor), which has received accelerated approval in the United States from the U.S. Food and Drug Administration (“FDA”) for use as an oral, once-daily therapy in patients 12 years of age and older with WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome, to increase the number of circulating mature neutrophils and lymphocytes. WHIM syndrome is a rare combined primary immunodeficiency and chronic neutropenic disorder. In connection with the our long term strategy to successfully complete the 4WARD Phase 3 trial in patients with moderate and severe chronic neutropenia, we are no longer prioritizing investment in the WHIM indication.

Current wording

We have one commercially approved product, XOLREMDI® (mavorixafor), which has received accelerated approval in the United States from the FDA for use as an oral, once-daily therapy in patients 12 years of age and older with WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome, to increase the number of circulating mature neutrophils and lymphocytes. WHIM syndrome is a rare combined primary immunodeficiency and CN disorder. We are committed to making XOLREMDI available to patients in need in the U.S. while maintaining our focus on our long-term strategy to successfully complete the 4WARD trial in patients with moderate and severe CN.

Previous wording

The following table summarizes the results of our operations for the three and nine months ended September 30, 2025 and 2024:

Current wording

The following table summarizes the results of our operations for the three months ended March 31, 2026 and 2025:

Previous wording

Co-pay assistance payments and rebates to U.S. government payors have comprised the majority of our gross-to-net revenue adjustments. Gross-to-net adjustments have been approximately 10% in 2025 year to date.

Current wording

Net product sales were $2.5 million and $0.9 million for the three months ended March 31, 2026 and 2025, respectively. Net product revenue growth over the prior year quarter was primarily due to an increase in the number of patients who have been prescribed the Company’s drug product. Gross-to-net adjustments were approximately 10% in the first quarter of 2026. Co-pay assistance payments and rebates to U.S. government payors have comprised the majority of our gross-to-net revenue adjustments.

Previous wording

Cost of revenue primarily consists of amortization of an intangible asset related to accrued and paid milestone payments associated with our Genzyme license agreement, and sales and sublicense-based royalty payments due under our Genzyme license agreement. Cost of revenue increased $4.9 million in thenine months ended September 30, 2025, as compared to the same period in the prior year, primarily due to additional royalties in the current nine period associated with sublicense income from our Norgine Agreement.

Current wording

Cost of revenue primarily consists of amortization of an intangible asset related to accrued and paid milestone payments associated with our Genzyme license agreement, cost of manufacturing drug product sold, and sales-based or sublicense-based royalty payments due under our Genzyme license agreement. Cost of revenue decreased $4.1 million in thethree months ended March 31, 2026, as compared to the same period in the prior year, primarily due to royalties in the prior year associated with sublicense income from our Norgine Agreement that did not reoccur in the current period.

Previous wording

Research and development expenses consist primarily of costs incurred in connection with the development of our product candidates, including employee salaries and related expenses, clinical development expenses, internal and third-party costs of manufacturing our drug products for use in our clinical trials. Research and development expenses also include costs related to compliance with regulatory requirements; and prior to the FDA’s approval of our drug product in the U.S. in the second quarter of 2024, payments made under third-party licensing agreements were charged to research and development expense.

Current wording

Research and development expenses consist primarily of costs incurred in connection with the development of our product candidates, including employee salaries and related expenses, clinical development expenses, internal and third-party costs of manufacturing our drug products for use in our clinical trials. Research and development expenses also include costs related to compliance with regulatory requirements.

Previous wording

Selling, general and administrative expenses consist primarily of salaries and related costs, including stock-based compensation, for personnel in sales and marketing, executive, finance, and administrative functions. Selling, general and administrative expenses also include direct and allocated facility-related costs as well as professional fees for legal, patent, consulting, investor and public relations, accounting, and audit services.

Current wording

General and administrative expenses consist primarily of salaries and related costs, including stock-based compensation, for personnel in executive, finance, and administrative functions. General and administrative expenses also include direct and allocated facility-related costs as well as professional fees for legal, patent, consulting, investor and public relations, accounting, and audit services.

Previous wording

Other expense, net, increased approximately $0.1 million in the three months ended September 30, 2025 as compared to the same period in the prior year primarily due to lower interest income earned on our marketable securities, partially offset by lower losses in the current period on fair value adjustments related to our Class C warrants. Other expense, net, decreased $4.9 million in thenine months ended September 30, 2025 as compared to the same period in the prior year primarily due to higher gains on fair value adjustments related to our Class C warrants in the current period, partially offset by lower interest income on our marketable security investment portfolio.

Current wording

Other income, net, decreased approximately $9.7 million in the three months ended March 31, 2026 as compared to the same period in the prior year primarily due to lower gains in the current period on fair value adjustments related to our Class C warrants, partially offset by higher interest income on ourmarketable security investment portfolio.

Previous wording

Public and Private Equity Offerings. Over the past several years we have funded our operations primarily from sales of common stock, warrants and prefunded warrants through both public offerings and private placements. Most

Current wording

Public and Private Equity Offerings. Over the past several years, we have funded our operations from sales of common stock, warrants and prefunded warrants through both public offerings and private placements. For example, most recently in October 2025 we completed an underwritten public offering of approximately 52.8 million shares of our common stock and prefunded warrants to purchase up to 700,000 shares of our common stock for net proceeds of $145.6 million, after underwriting discounts and offering expenses.

Previous wording

ATM Sales Agreement. We are party to a Controlled Equity Offering SMSales Agreement (“ATM”), dated as of August 7, 2020, pursuant to which we may offer and sell shares of our common stock through one or more investment banks. To date and for the nine months ended September 30, 2025, we have sold $23.6 million and $9.0 million, respectively, of our common stock, net of offering costs, under the ATM. Pursuant to our Registration Statement on Form S-3 that became effective on August 24, 2023 and the related ATM prospectus contained therein, we may offer and sell shares of our common stock having an aggregate offering price of up to an additional $66.0 million.

Current wording

ATM Sales Agreement. We were a party to a Controlled Equity Offering SMSales Agreement (“ATM”), dated as of August 7, 2020, pursuant to which we periodically sold shares of our common stock through one or more investment banks. We have sold $24.2 million of our common stock, net of offering costs, under the ATM. We terminated the ATM effective March 30, 2026.

Previous wording

Hercules Loan Agreement. We are a party to a loan and security agreement (the “Hercules Loan Agreement”), which provides for a term loan facility of up to $107.5 million, under which we have borrowed an aggregate of $75.0 million of term loans to date, representing the maximum borrowings as of September 30, 2025. The term loan facility requires that we make interest-only payments through maturity on July 1, 2027 and requires that we meet certain operational and financial covenants. See Note 8 to the condensed, consolidated financial statements contained herein for a full description of our Hercules Loan Agreement.

Current wording

Hercules Loan Agreement. We are a party to a loan and security agreement (the “Hercules Loan Agreement”), which provides for a term loan facility of up to $107.5 million, under which we have borrowed an aggregate of $75.0 million of term loans to date, representing the maximum borrowings as of March 31, 2026. The term loan facility requires that we make interest-only payments through maturity on July 1, 2027 and requires that we meet certain operational and financial covenants. See Note 11 to our Annual Report on Form 10-K as filed with the SEC on March 17, 2026 for a full description of our Hercules Loan Agreement.

Previous wording

During the nine months ended September 30, 2025, cash used in investing activities of $8.7 million, primarily include net sales of short-term marketable securities. During the nine months ended September 30, 2024, cash provided by investing activities of $75.6 million included $105.0 million in cash proceeds from the sale of a priority review voucher obtained as a result of the approval of our drug product by the FDA, partially offset by cash outflows of $7.0 million in license payments classified as the acquisition of an intangible assets, $22.1 million of net investments of short-term marketable securities and the acquisition of equipment.

Current wording

During the three months ended March 31, 2026, cash provided by investing activities of $19.3 million was primarily due to net sales of short-term marketable securities. During the three months ended March 31, 2025, cash used in investing activities of $3.1 million was due to net investment in short-term marketable securities.

Previous wording

October 27, 2025, we closed an underwritten offering of shares of our common stock and, in lieu of common stock to certain investors, pre-funded warrants to purchase shares of our common stock, for net proceeds of approximately $145.6 million, after deducting underwriting discounts and commissions and estimated offering expenses, which further extends our ability to fund our operations and financial obligations. Until we reach profitability, we will need to raise additional capital, which cannot be assured, to fund our operations and meet our financial obligations beyond this period. Such additional capital could be raised through a combination of equity offerings, debt financings, other third-party funding, marketing and distribution arrangements, or other collaborations and strategic alliances. If we are unable to obtain funding, we could be forced to delay, reduce, or eliminate some or all of our research and development programs, product portfolio expansion or commercialization efforts, which would adversely affect our business prospects, or we may be unable to continue operations and may need to restructure our obligations in a court-supervised process or otherwise.

Current wording

We expect to continue to incur operating losses as we advance our lead drug candidate through the 4WARD trial. Until we reach profitability, we will need to raise additional capital, which cannot be assured, to fund our operations and meet our financial obligations beyond this period. Such additional capital could be raised through a combination of equity offerings, debt financings, other third-party funding, marketing and distribution arrangements, or other collaborations and strategic alliances. If we are unable to obtain funding, we could be forced to delay, reduce, or eliminate some or all of our research and development programs, product portfolio expansion or commercialization efforts, which would adversely affect our business prospects, or we may be unable to continue operations and may need to restructure our obligations in a court-supervised process or otherwise.

Previous wording

During the three months ended September 30, 2025, there were no material changes to our critical accounting policies as reported for the year ended December 31, 2024 as part of our Annual Report on Form 10-K other than as updated in Note 2 of these condensed consolidated financial statements. Also see Note 2 under the heading “Recently Adopted Accounting Pronouncements” for new accounting pronouncements or changes to the accounting pronouncements during the three months ended September 30, 2025.

Current wording

During the three months ended March 31, 2026, there were no material changes to our critical accounting policies as reported for the year ended December 31, 2025 as part of our Annual Report on Form 10-K. See Note 1 to the unaudited interim condensed consolidated financial statements included in this Quarterly Report on Form 10-Q under the heading Recently Issued Accounting Standards Not Yet Adopted for new accounting pronouncements or changes to the accounting pronouncements during the three months ended March 31, 2026.